Complexing compositions

Details Complexing compositions Complexing compositions

2000-07-31

2001-07-10

Clardy, S. Mark (Department: 1616)

Plant protecting and regulating compositions

Plant growth regulating compositions

Aquatic plant regulator

C504S187000, C424S638000, C424S641000, C424S646000

Reexamination Certificate

active

06258750

ABSTRACT:

TECHNICAL FIELD
The invention relates to pesticidal, algicidal, herbicidal and fungicidal compounds and compositions containing them. The invention also relates to the use of a specific complexing agent for preparation of a composition for inhibition or stabilisation of algae, plant and fungi growth.
BACKGROUND TO THE INVENTION
In almost all water systems such as rivers, lakes, streams, pools, industrial and ornamental water systems, irrigation systems etc., excessive growth of algae, (aquatic) plants and fungi can occur, which can be a severe problem, in particular because it can impart a distastefull appearance and odour to the water, it can interfere with the flow of the water, and may be harmfull to the growth or health of other life.
In the past, various types of algicides and herbicides have been employed in an attempt to control the growth of algae and aquatic plants. For example, dipyridylium compounds, as disclosed in U.S. Pat. No. 2,823,987 have been widely used to control the growth of algae and aquatic plants, and while these compounds have been effective, there are certain varieties of aquatic plants, such as Hydrilla, against which the dipyridylium compounds are relatively ineffective. Moreover, conventional herbicides have relatively little effect against algae.
Since the tun of the century, copper has been known as an effective control on algae, in particular copper sulfate. Not only is it probably one of the most effective chemical algicides it is also safe to use. Also cobalt is know to have algicidal properties. However, the solubility of copper salts such as sulfate salts, is severely affected by increasing alkaline pH's. In waters containing bicarbonates, carbonates and/or a pH over 7, it has long been known that copper sulfate is ineffective because of copper precipitating in the form of copper hydroxide or copper carbonate. Since the algicidal properties of copper sulfate are due to the copper ions, without these toxic copper ions, copper sulfate is essentially hainrmless to algae and the like.
Chelating agents, such as EDTA, have been used in combination with copper ions, to improve its solubility in alkaline environment, as for example described in U.S. Pat. No. 5,407,899 and EP 259,525. The chelating agent releases and maintains the toxic forms of copper, i.e. Cu
++
, in the water.
However, the inventors have now found that not all chelating effectively release or maintain the level of dissolved copper ions. They have also found that a chelating agent does not perform effectively in all types of water system.
The inventors have now found that this can be due to the fact that these chelating agents may bind to other metal ions which may be present in the water. It has been found that in particular the presence of calcium ions can reduce the efficiency or effectiveness of certain chelating agents, such as EDTA. The nature of the systems and the methods wherein the chelating agents are used is such, that the presence of calcium ions is unavoidable or even desirable. Thus, this can lead to reduction of the chelating of the copper or cobalt ions, which subsequently can form insoluble salts and are thus no longer effective algicides.
This problem can be even more severe in several applications, where calcium-containing compounds are additionally required as algicides, for example calcium hypochlorite.
However, the inventors have now found that specific complexing agents are excellent complexing agents for forming complexes with the selected metal ions, useful in algicidal, herbicidal, fungicidal compositions, such as copper and cobalt ions, in particular in the presence of calcium ions.
SUMMARY OF THE INVENTION
The invention provides an aqueous pesticidal, algicidal, herbicidal and/or fungicidal composition, comprising calcium ions and one or more metal ions, selected from the group comprising Cu, Fe, Zn, Ni and Co (herein referred to as ‘the selected metal ions’), and a complexing agent, whereby the −log
10
C
T
is equal to or greater than the smallest value of A or B, where
A=−log
10
(L
T
−M
T
); and B=K
1
(1−K
2
{square root over (I)})(1−K
3
.exp(−K
4
.P)),
wherein C
T
is the total concentration of calcium ions, L
T
is the total concentration of incomplexing agent, M
T
is the total concentration of the metal ions, selected from the group consisting of Cu, Fe, Zn, Ni and Co; P is the pH of the composition, I is the ionic strength of the composition, wherein all concentrations are in moles/liter, where K1, K2, K3 and K4 are the following constants for the metals ions:
Cu
++
Fe
+++
Zn
++
Ni
++
Co
++
K1
11.062
5.754
7.963
13.098
7.642
K2
0.496
0.479
0.619
0.535
0.652
K3
2.479
9385.0
24.202
1.473
32.069
K4
0.227
1.092
0.506
0.126
0.532
Preferably, the selected metal ions are comprised in a complex with the complexing agent.
The invention also provides pesticidal, algicidal, herbicidal and/or fungicidal compositions, containing a complexing agent containing EDDS and one or more selected metal ions, preferably cobalt, zinc or copper ions.
The invention also relates to the use of a complexing agent and a selected metal ion, preferably a complex thereof, for preparation of pesticidal, algicidal, herbicidal and/or fungicidal compositions.


REFERENCES:
patent: 3158635 (1964-11-01), Kezerian et al.
patent: 3930834 (1976-01-01), Schulteis et al.
patent: 5741555 (1998-04-01), Wilson et al.
patent: 6069113 (2000-05-01), Kierzkowski et al.
Abstracts #P002100086, Derwent Publications Ltd., London, GB, Jul. 7, 1993, Class C01, An 94-365177, Section ch, Week 9445.
Abstracts #84913 (XP00210084), Chemical Abstracts, vol. 117, No. 9, Aug. 31, 1992, Columbus, OH, Kovaleva, I.B. et al: “Dicarboxylic acis-biometal complexes as escologically safe stimulators for plant growth”.
Abstracts #137517 (XP002100085), Chemical Abstracts, vol. 106, No. Apr. 27, 1987, Columbus, OH, Perov, N.N. et al.: “Testing iron, zinc, and manganese complexes with ethylenediaminediscuccinic and iminodisuccinic acids in chlorotic vineyards”.
Abstracts #XP00210087, Derwent Publications Ltd., London, GB, Sep. 23, 1983, Class C04, An 84-145630, Section Ch, Week 8423.
Abstracts #XP002100088 & JP 0913687, Derwent Publications Ltd., London, GB, May. 27, 1987, Class C04, An 97-337018, Class C04, An 97-337018, section Ch, Week 9731.

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